US3746462A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Stage seals for a turbine
Assignee: Mitsubishi Heavy Industries Ltd
•
Filing: 1971-06-29
•
Granted: 1973-07-17
•
Expires: 1991-06-29
Abstract
Abstract A plurality of ducts disposed in a stationary blade ring diaphragm of a steam turbine, the ducts have inlets disposed upstream of the last downstream fin of a labyrinth seal formed between the diaphragm and a rotor. The ducts extend through a plurality of stationary blades disposed in the diaphragm, and have outlets on the downstream side of the diaphragm adjacent a casing, for reducing the total quantity of steam bypassing the stationary and rotating blades forming one stage of the turbine by directing steam, which passes through the labyrinth seal adjacent the rotor, to an area upstream of a labyrinth seal associated with a shroud ring encircling the rotatable blades of this stage of the turbine.
Inventors
- 👤 S Fukuda
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 16:36
CPC Classifications
F; F01; F01D; F01D11/00; F01D11/08; F01D11/10; Y; Y10; Y10S; Y10S415/00; Y10S415/914
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
191 words
A steam turbine having an annular array of circumferentially spaced stationary blades disposed upstream of an annular array of circumferentially spaced rotatable blades and said stationary blades having an inner shroud ring, a rotor upon which said rotatable blades are mounted, a casing encircling said blades and rotor, and a labyrinth seal between said shroud ring and said rotor having a plurality of circumferential axially spaced fins encircling the rotor, said annular array of stationary blades having at least one duct extending from a space immediately upstream of the last downstream fin forming the labyrinth seal, radially through at least one stationary blade, and then to a downstream side of said stationary blades adjacent said casing, said duct being disposed to allow a small portion of the steam which flows through said labyrinth seal to flow into said duct, and through said duct to said downstream side of said stationary blades adjacent said casing, and then to flow between said annular array of rotatable blades and said casing to reduce the total amount of motive fluid bypassing said blades and not doing useful work, thereby increasing the efficiency of said turbine.
Claim 2
Dependent Claim
191 words
A steam turbine having an annular array of circumferentially spaced stationary blades disposed upstream of an annular array of circumferentially spaced rotatable blades and said stationary blades having an inner shroud ring, a rotor upon which said rotatable blades are mounted, a casing encircling said blades and rotor, and a labyrinth seal between said shroud ring and said rotor having a plurality of circumferential axially spaced fins encircling the rotor, said annular array of stationary blades having at least one duct extending from a space immediately upstream of the last downstream fin forming the labyrinth seal, radially through at least one stationary blade, and then to a downstream side of said stationary blades adjacent said casing, said duct being disposed to allow a small portion of the steam which flows through said labyrinth seal to flow into said duct, and through said duct to said downstream side of said stationary blades adjacent said casing, and then to flow between said annular array of rotatable blades and said casing to reduce the total amount of motive fluid bypassing said blades and not doing useful work, thereby increasing the efficiency of said turbine.
Claim 3
Dependent Claim
35 words
A turbine as set forth in claim 1, wherein a plurality of radial ducts extending through a plurality of stationary blades, the inlets to the ducts being disposed upstream of the last downstream circumferential fin.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-07-16 | 1977-01-15 | 1977-07-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-07-16 | 1981-01-15 | 1981-07-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-07-16 | 1985-01-15 | 1985-07-17 | $7700.00 | Window Closed / Lapsed |